1. Field of the Invention
This application was filed claiming Paris Convention priority of Japanese Patent Application No. 2007-186710, the entire content of which is herein incorporated by reference.
The present invention relates to a polypropylene-based resin composition and a molding made from the same. More particularly, the present invention relates to a polypropylene-based resin composition which is less likely to emit a volatile organic compound contained therein to the outside, and is also excellent in tensile strength, impact strength and molding processability, and to a molding made from the same.
2. Description of the Related Art
Among thermoplastic resins, a polypropylene-based resin is a typical resin which is inexpensive and is lightweight, and is also excellent in characteristics such as molding processability, mechanical characteristics, heat resistance, long-term heat degradation resistance, and are therefore widely used in applications, for example, various containers, food packaging materials, caps of containers such as bottles, stationery, daily necessities, fibers for carpets and sofas, automotive interior/exterior materials, household appliance materials, and building materials such as interior materials of buildings and houses. Since there is a fear for a sickhouse (indoor air pollution) problem with building materials such as interior materials of buildings and houses, it has recently been required to decrease volatile organic compounds (VOC), which are reported as causative substances of the sickhouse problem, for a resin material to be used. Specific measures have been studied about thirteen kinds of VOC including formaldehyde. The sickhouse problem is considered as the objective substance in not only building materials but also interior materials of vehicles such as automobiles, and the use of resin materials containing less VOC is required.
For example, Japanese Unexamined Patent Publication (Kokai) No. 8-3381 discloses a polyolefin-based composition comprising a polyolefin, a lubricant, and a zeolite which has a specific molar ratio Si/Al, an average particle diameter and water adsorption properties and is also represented by a specific formula. The publication describes that a container cap made from the composition does not cause deterioration of taste or smell of foods in the container.
Japanese Unexamined Patent Publication (Kokai) No. 10-1568 discloses a polyolefin-based composition comprising a polyolefin, and one or more kinds of adsorptive inorganic substances selected from the group consisting of an inorganic filler, a zeolite, a fraipontite-silica composite and a hydrotalcite. The publication describes that the composition is less likely to cause generation of an unpleasant odor under heating and gives a molding having excellent heat fading resistance, and such a molding is suited for use as a food packaging container.
Japanese Unexamined Patent Publication (Kokai) No. 11-140331 discloses a synthetic resin composition comprising a synthetic resin component and an artificial zeolite. The publication describes that generation of a harmful gas such as a hydrogen chloride gas is suppressed upon incineration of products made from the composition, and also high combustion efficiency enables less generation of residual ash.
Japanese Unexamined Patent Publication (Kokai) No. 2000-297221 discloses a synthetic resin composition comprising a synthetic resin component and an alkali earth metal type synthetic zeolite, and a product produced therefrom. The publication describes that generation of a harmful gas such as hydrogen chloride or dioxin is suppressed when products made from the composition are incinerated.
Japanese Unexamined Patent Publication (Kokai) No. 2006-257404 discloses a low-odor resin composition comprising a thermoplastic resin and a hydrophobic silica aluminosilicate having a specific molar ratio SiO2/Al2O3. The publication describes that various original characteristics of the thermoplastic resin in the composition are not impaired and generation of an odor during melt-kneading for preparation of the composition, heating at high temperature in molding processing, storage of the molding at high temperature or on use is remarkably reduced, and also the molding is excellent in appearance.
However, from the viewpoint of environmental protection, it is required to decrease emission of VOC from the resin compositions described in the aforementioned publications and the products made from the compositions, especially aldehydes.